A recent development in mobile cellular systems is the ability to transfer short messages between an application residing on a mobile station and another application residing on a mobile network element, such as a message centre for example. This service is sometimes referred to as a SMS (short message service). These messages might include mobile originated point-to-point messages, mobile terminated point-to-point, and broadcast for example. These messages, while short, are typically much longer than a conventional page.
The conventional approach to short message delivery to an idle mobile station is to flood all the paging channels with the message. A problem with this approach is that a lot of paging bandwidth is needlessly wasted. Because of this, this conventional approach is biased towards smaller SMS message payloads and requires more messaging to deliver large payloads. With the industry moving more and more towards data services, is would be advantageous to have a short message service capable of efficiently delivering longer messages.
There is no problem with sending messages to mobile stations which have an active traffic channel since the messages can also be sent over the traffic channel without wasting any additional paging channel resources. However, it is undesirable to set up a traffic channel specifically for sending a message unless this is absolutely necessary. This is because the traffic channels are the main revenue generating units for the mobile network and need to be conserved.